Crankcase ventilating valve having rotatable metering plunger



Nov. 28, 1967 w. I. BARNES 3,354,898

CRANKCASE VENTILATING VALVE HAVING ROTATABLE METERING PLUNGER Filed May2, 1966 2 Sheets-Sheet 1 ATTORNEKS' W. l. BARNES Nov. 28, 1967 CRANKCASEVENTILATING VALVE HAVING ROTATABLE METERING PLUNGER 2 Sheets-Sheet 2Filed May 2, 1966 MO'ld SOOBSVE) INVENTOR William I. Barnes UnitedStates Patent 3,354,818 CRANKQASE VENTILATING VALVE HAVING ROTATABLEMETERING PLUNGER William I. Barnes, Birmingham, Mich, assignor toStandard Screw Company, a corporation of New Jersey Filed May 2, 1966,Ser. No. 546,995 7 Claims. (Cl. 137-331) ABSTRACT OF THE DKSCLOSURE Aflow meteringvalve adapted for use in an automotive crankcaseventilating system comprising a generally elongated valve housing havingan inlet end, an outlet end, and a bore provided with a restrictedportion intermediate its ends to form a metering orifice. A generallyelongated metering plunger is provided in the bore of said housing and asealing member is disposed adjacent the inlet end of said housing, saidplunger and said sealing member being magnetically attracted to preventflow through said valve until a predetermined flow pressure is attained.A spring is movably mounted in said housing and yieldably supports theplunger after the predetermined flow pressure has been attained topermit axial movement of said plunger relative to said orifice inresponse to changes in pressure in said valve housing.

This invention is a continuation-in-part of application Serial No.436,439 filed March 2, 1965, now abandoned.

This invention relates to fluid flow control and more particularly tometering valves adapted for use in positive crankcase ventilatingsystems for engine operated vehicles so as to materially reducedischarge into the atmosphere of smog inducing blow-by accumulating inthe crankcase.

One system of attaining positive crank-case ventilating involves the useof a conduit communicating the crankcase with the intake manifold sothat the manifold vacuum will draw air and the blow-by through theconduit from the crankcase and deliver the blow-by laden air back to thecylinders. However, the performance of the engine will not besatisfactory unless the prescribed amount of air for the selectedcarburetor setting can be controlled in a continuous flow.

Accordingly, it is necessary to provide some means to precisely meterthe flow. One type of device which has been found generally suitable forpositive crankcase ventilation is a spring loaded valve having a plungerof a varying cross section along its length cooperating with a meteringorifice provided in the bore of the valve housing. This plunger movesaxially in the bore in response to changes in pressure in the manifoldand the movement of the plunger varies the size of the effective fiowmetering orifice.

A metering valve of the type described above must be capable ofpermitting delivery of a prescribed amount of the blow-by laden air in acontinuous manner without interfering with proper engine performance,and must maintain this capability despite the fact many different typesof engines are to be served. Thus, it is the practice of enginemanufacturers, to assure as little interference as possible with properengine performance, to require that these valves produce a smooth flowcurve when tested to determine the fluid flow under various pressuredifferentials across the valve, and it is required that the valves do sowith the limits of the flow curves by the manufacturer for each of itsengines.

It was found that one of the problems with spring loaded valves of thetype having a free floating pin, particularly those designed to centerthe pin to prevent the pin from contacting the valve housing and thewalls, was axial oscillation or jiggling of the metering plunger under3,354,893 Patented Nov. 28, 1967 operating conditions caused by pressurefluctuations. Such oscillations created such instability of the meteringpin or plunger as to cause irregular rather than smooth fiow curves. Tosolve this problem, the spring which surrounded the plunger was arrangedso as to cock the plunger in the bore of valve housing so that the pinwould rub against wall portions of the metering orifice, and thus dampenout the inst-ability of the plunger during metering of the flow. Inarranging the spring so as to cant the plunger in the axial bore of thevalve housing, one means found satisfactory was to laterally offset theinnermost coil of the spring and to make this coil of a size so that itwould embrace the plunger about the pin adjacent the head portion in apress fit.

A problem that occurred with valves of the type described above was thebuild-up on the metering plunger of sludge or gunk present in theblow-by passing through the valve body. If too much gunk becamedeposited on the plunger this would also interfere with proper engineperformance due to a decrease of the flow through the valve.

Accordingly, the primary aim of the present invention is to providemeans to prevent an undesirable build-up of gunk on those portions ofthe canted plunger which do not ordinarily rub against the wall portionof the metering orifice.

A further problem occurred in the starting of an engine utilizing valvesof the type described above. It is well known that a large volume of airflow is required when the intake manifold vacuum is low during maximumthrottle conditions. However, during starting of the engine, when theintake manifold vacuum is also low, an excessive amount of air passesthrough the valve from the crankcase causing a leaning out of theair-fuel ratio, and therefore, poor starting conditions.

It is, therefore, another aim of the present invention to provide ameans which shuts off the flow of air through the valve when startingthe engine and, thereafter, permits the air to attain a normal flow.

Briefly summarized, the present invention provides a flow meteringdevice utilizing a spring loaded plunger. The spring is a compressionspring provided with a laterally ofiset coil so as to cock or cant theplunger to dampen oscillations by reason of the plunger rubbing againstadjacent wall portions of a metering orifice provided in the bore of thevalve housing. Means are provided on the plunger to frictionally receivethe laterally offset coil of the compression spring yet to permit freerotation of the plunger relative to the laterally otfset coil. As aconsequence, in operation, the plunger will rotate in the valve housingand metering orifice and substantially all portions of the periphery ofplunger that cooperate with the orifice in metering the flow will rubagainst wall portions of the orifice and prevent any material depositingof gunk on the corresponding portions of the plunger.

As a further aid in the prevention of build-up of gunk on the valveassembly, the metering orifice may be made of a plastic material and theplunger may be chromeplated.

Further, a magnetic backfire washer may be provided adjacent the inletend of the valve structure, the magnetic properties of the washer beingsuch that the steel plunger is held fast against the washer to shut offair flow until a predetermined manifold vacuum is obtained, at whichtime the plunger will lift off the washer and assume its normal fiowposition.

Reference is now made to the accompanying drawings for a betterunderstanding of the nature and objects of the present invention, thesedrawings being but an illustration of the best mode contemplated by theapplicants for carrying out the invention, but not to be taken asrestrictions or limitations on its scope.

FIG. 1 is a skeleton elevation of a typical installation of a positivecrankcase ventilation system;

FIG. 2 is a vertical sectional view, with portions in elevation forpurposes of illustration, showing a valve structure incorporating thepresent invention with the metering plunger and spring assembly disposedin the position it assumes when the automotive engine is beingaccelerated;

FIG. 3 is a view like FIG. 2, showing the position of the meteringplunger and spring assembly when the engine is idling;

FIG. 4 is also a vertical sectional view like FIG. 2, showing theposition of the plunger and spring assembly in the event of backfire inthe engine;

FIG. 5 is an elevational view of the metering plunger for the valvestructure shown in FIGS. 2, 3 and 4;

FIG. 6 is an end elevational view of the valve structure shown in FIGS.2, 3 and 4 taken from the inlet end of the device;

FIG. 7 is a cross section on line 77 of FIG. 2;

FIG. 8 is a cross section on line 8-8 of FIG. 3; and

FIG. 9 is a graphical representation of two flow curves obtained forthis type engine utilizing the present invention.

Reference is now made to the details of the invention wherein, it willbe noted as shown in FIG. 1, the valve, generally indicated by referencenumeral 10, may be suitably attached to the rocker arm cover 12 of theen- :gine with the outlet end 18 up. A flexible tube or hose 14 may becoupled at one of its ends to the outlet end 18 of the valve structureand at its other end to the intake manifold 16 of the engine. However,these means for interconnecting the parts of the positive crankcaseventilating system form no part of this invention since theseessentially plumbing details are well known to those skilled in the art.

The inlet end 20 of the valve structure is provided with a countersink22 in the axial bore of a generally cylindrical housing 24 to receive aback-fire washer 26 fitted into the countersink. Washer 26 may bepermanently fixed in countersink 22 or the latter may be provided withan annular groove 28 to receive a generally C-shaped retainer clip 30.The clip 30 seats in the groove 28 abutting adjacent portions of theback-fire washer 26 disposed inwardly of the retainer clip 30. Theretainer clip 30 may be provided with means to facilitate removal of theclip with a suitable prying tool such as laterally extending fingers 32.

The bore of the housing 24 is reduced in cross section intermediate theinlet and outlet ends of the valve structure as best shown in FIGS. 2, 3and 4. The junction of the reduced portion of the bore of the housingwith the portion of larger cross section defines a metering orifice 34provided for cooperation with a generally elongated solid meteringplunger 36 to meter the flow of crankcase blow-by through the bore ofhousing 24.

The metering plunger 36 has an end portion 38 of reduced cross sectionwhich as it extends inwardly joins with an intermediate portion 40 ofthe body of the plunger. The port-ion 40 progressively increases incross section in the direction of the opposite or inlet end of themetering plunger and merges with another intermediate portion 42 whichmay progressively increase in cross section in the direction of theinlet end of the plunger, as shown in the drawings, or which may be of auniform diameter.

It will be noted that the metering plunger 36 is of a length that theend portion 38, which constitutes the outlet end of the plunger, iswithin the confines of the orifice 34 in all positions of operation.Further, the end portion 38 and the intermediate portions 40 and 42constitute the effective portions of the plunger for varying the size ofthe orifice for metering purposes as the plunger moves axially to andfro in response to the changes in pressure in the manifold,

Adjacent the intermediate portion 42, in the direction of the outlet endof the pin, the metering plunger is provided with a further portion 44which is of reduced cross section, relative to portion 42, and mergeswith a portion 46 of a progressively increasing cross section toward theinlet end of the plunger.

The inlet end of metering plunger 36 is provided with an enlargedportion 48 constituting a head portion. Inwardly of the head portion 48,the metering plunger is provided with an annular groove or undercut 50constituting a seat to receive a laterally offset coil 52 of acompression spring 54 in the bore of the housing. This constructionpermits free radial rotation of the plunger relative to the spring andyet resists axial movement of the plunger. Coil 52 of the compressionspring may be laterally offset relative to the intermediate coils 56 andan outermost coil 58, the coils 56 and 58 being concentrically disposedrelative to each other. Spring 54 normally urges the plunger in thedirection of the valve inlet 20.

By providing the metering plunger 36 with the undercut 50, between thehead portion 48 and the enlarged portion 46, the laterally offset coil52 fits into the undercut and thus cocks the metering plunger so that itis not centered in the bore. The coil 52 fits in the undercut relativelyloosely, thus permitting substantially free radial rotation of themetering plunger 36 relative to the coils of the compression spring 54.

It is to be understood that it is not absolutely necessary that coil 52be laterally offset, as long as it performs the function of cocking theplunger so that it rubs against a portion of the metering orifice. Forexample, the coil 52 could be coaxial with the remaining coils, but bentin a manner to urge the plunger into the above mentioned position.

The outermost coil 58 of the compression spring while coaxial with theintermediate coils 56 is of a lesser diameter. This coil 58, when thevalve is in operation, abuts a stop shoulder 60 formed at the junctionof the restricted portion of the bore of the valve housing 24.

It will be noted that the metering plunger and spring assembly and theback-fire washer 26 may be effectively and removably retained within thevalve housing 24 by the C-shaped retaining clip 28, which as statedabove can itself be removed by a prying tool manipulated against thelaterally offset fingers 32.

As a further aid in preventing the build-up of gunk in the valveassembly, at least the portion of the bore defiining the meteringorifice may be made of a plastic such as nylon, this material beingutilized due to the fact that nylon has a resistance to sludge andvarnish that tend to form in the valve assembly. For similar reasons,the plunger 36may be chrome-plated in addition, or as an alternate, tomaking the bore of nylon.

In operation, as best shown in FIGS. 2 and 3, the metering plunger isaxially displaced to and fro in response to pressure changes across thevalve, and the desired quantity of flow is metered by variations of theeffective size of the metering orifice 34 defined by the mouth of therestricted portion of the bore of valve housing 24. Due to the laterallyoffset coil 52 seated in the undercut 50, the metering plunger 36 iscocked or canted so that portions along the length of one side of theplunger rub against the adjacent portion of the walls of the meteringorifice while the side of the plunger opposite from the side ridingagainst the wall portion is spaced from all wall portions of the orificeto permit fluid flow through said space. Inasmuch as the plunger isrotatable within the compression spring 54, the rubbing will occurthroughout the periphery of the effective flow metering portions of themetering plunger along its length, thus preventing an undue build-up ofgunk on such portions of the plunger. What is more, there are differentrelative motions or movements in the spring and plunger assembly in thatnot only does the entire assembly rotate with respect to the adjacentwalls of the valve housing, but the plunger rotates within the spring.

According to another feature of this invention, the backfire washer 26may be of a magnetic material and plunger 36 of steel, in order that theplunger may be held fast against the washer during engine starting untila predetermined vacuum is obtained across the valve. As stated earlier,this eliminates the passing of an excessive amount of air through thevalve from the crankcase during starting which causes an undesirableleaning out of the air fuel ratio. Referring to FIG. 9 of the drawings,a pair of engine flow curves obtained utilizing this magnetic washer aredepicted, the solid curve representing the flow obtained as the intakemanifold vacuum increase from a zero vacuum to a positive vacuum, andthe broken curve representing the flow obtained as the vacuum decreasesfrom this positive vacuum to zero vacuum.

As seen from the curves, a large volume of flow from the crankcase tothe intake manifold is required when the intake manifold vacuum isrelatively low which normally occurs during maximum throttle conditionsas shown by section B-C of the curve. Also, a smaller volume of emissionflow is required when the intake manifold vacuum is high during minimumor idle throttle conditions as shown at section C-D of the curve.However, during the starting conditions shown at section AB of thecurve, a problem exists due to the fact that, immediately upon amanifold vacuum being created while the engine is being started, anexcessive air flow results which leads to an undesirable leaning out ofthe air-fuel ratio. The applicant has solved this problem by providing abackfire washer 26 of the proper magnetic properties so that plunger 26is held fast against the washer during starting of the engine, thuseliminating air flow despite the existence of a low manifold vacuumduring this time. As seen from section A-B of the solid curve obtainedfrom this arrangement, the air flow remains at zero despite the manifoldvacuum increasing from zero to a predetermined amount, which may beapproximately 0.5 inch Hg. A vacuum in excess of this amount causes aforce to be exerted against the plunger which is greater than that ofthe magnetic force, the plunger thus being released from the washer toassume its position during normal flow conditions as represented bysection 13-1) of the curve. As the intake manifold vacuum decreases froma positive to a Zero value, the gaseous flow follows the broken curve asseen in FIG. 9.

It is to be understood that other variations of the above arrangementare possible as long as the above magnetic creating hysteresis ispresent. For example, the plunger could be magnetic and the washer of amaterial that is responsive thereto.

Accordingly, this invention results in a metering valve for positivecrankcase ventilating system capable of long use without becomingclogged and capable of producing the desired flow of blow-by at alltimes without seriously afi'ecting proper engine performance.

What is claimed is:

1. A flow metering valve adapted for use in an automotive crankcaseventilating system comprising a generally elongated valve housing havingan inlet end and an outlet end, said housing having a bore provided witha restricted portion intermediate its ends constituting a meteringorifice, a generally elongated metering plunger in the bore of saidhousing, one end portion of said plunger extending into said orifice, asealing member disposed adjacent the inlet end of said housing, saidplunger and said sealing member being magnetically attracted to preventflow through said valve until a predetermined fiow pressure is attained,and support means movably mounted in said housing, engaging saidrestricted portion of said housing, and yieldably supporting saidplunger after said predetermined flow pressure has been attained topermit axial movement of said plunger relative to said orifice inresponse to changes in pressure in said valve hous'mg, said supportmeans loosely engaging said plunger to permit relative movement betweensaid support means and said plunger.

2. The combination defined by claim 1, including retaining meansremovably mounted in the bore of said housing to retain said plunger andsupport means in said housing.

3. The combination defined by claim 1, wherein said support meanscomprises a compression spring having a plurality of coils surroundingsaid plunger, one of said coils being laterally offset relative to theother coils and positioned around said plunger so as to cause portionsof said plunger along its length to rub against portions of the wall ofsaid orifice during axial movement of the plunger in response to achange of pressure.

4-. The combination defined by claim 3, wherein the side of said plungeropposite from the side riding against the wall portion is spaced fromall wall portions of the orifice to permit fluid flow through saidspace.

5. The combination defined by claim 1, wherein said sealing member is amagnetic washer, the magnetic field of which attracts said plungerthereto.

6. The combination defined by claim -1, wherein said plunger is of amagnetic material, the magnetic field of which attracts the plunger tosaid sealing member.

7. The combination defined by claim 1, wherein at least the portion ofthe bore defining the metering orifice is of a plastic material and saidplunger is chrome-plated.

References Cited UNITED STATES PATENTS 2,145,977 2/1939 Foster 251324 X3,111,138 11/1963 Humphreys 137480 3,165,097 1/1965 Lowther 1374833,198,208 8/1965 Tramontini 137480 3,199,524 8/1965 Mitchell 251 X3,225,752 12/ 1965 Robinson 12 31 19 3,225,753 12/1965 Bintz 251-65 X3,263,699 8/1966 Givler 137-480 ALAN COHAN, Primary Examiner.

HAROLD W. WEAKLEY, Examiner.

1. A FLOW METERING VALVE ADAPTED FOR USE IN AN AUTOMOTIVE CRANKCASEVENTILATING SYSTEM COMPRISING A GENERALLY ELONGATED VALVE HOUSING HAVINGAN INLET END AND AN OUTLET END, SAID HOUSING HAVING A BORE PROVIDED WITHA RESTRICTED PORTION INTERMEDIATE ITS ENDS CONSTITUTING A METERINGORIFICE, A GENERALLY ELONGATED METERING PLUNGER IN THE BORE OF SAIDHOUSING, ONE END PORTION OF SAID PLUNGER EXTENDING INTO SAID ORIFICE, ASEALING MEMBER DISPOSED ADJACENT THE INLET END OF SAID HOUSINGM SAIDPLUNGER AND SAID SEALING MEMBER BEING MAGNETICALLY ATTRACTED TO PREVENTFLOW THROUGH SAID VALVE UNTIL A PREDETERMINED FLOW PRESSURE IS ATTAINED,AND SUPPORT MEANS MOVABLY MOUNTED IN SAID HOUSING, ENGAGING SAIDRESTRICTED PORTION OF SAID HOUSING, AND YIELDABLY SUPPORTING SAIDPLUNGER AFTER SAID PREDETERMINED FLOW PRESSURE HAS BEEN ATTAINED TOPERMIT AXIAL MOVEMENT OF SAID PLUNGER RELATIVE TO SAID ORIFICE INRESPONSE TO CHANGES IN PRESSURE IN SAID VALVE HOUSING, SAID SUPPORTMEANS LOOSELY ENGAGING SAID PLUNGER TO PERMIT RELATIVE MOVEMENT BETWEENSAID SUPPORT MEANS AND SAID PLUNGER.